Feminine hygiene absorbent personal care articles are often used to collect and retain body fluids, liquids or exudates containing menses or blood. In the context of such products, comfort, absorbency, and discretion are three main product attributes and areas of concern for the wearer. In particular, wearers are often interested in knowing that such products will absorb significant volumes of menses exudates in order to protect their undergarments, outergarrnents, or bedsheets from staining, and that such products will help them avoid the subsequent embarrassment brought on by such staining. Wearers are also interested in using products that cannot be seen or felt through their undergarments.
Feminine hygiene absorbent personal care articles, such as sanitary napkins, pads and pantiliners, typically include at least one or more absorbent layers enclosed between a body-facing, liquid permeable topsheet layer and a garment-facing liquid impermeable backsheet layer. The absorbent layers and/or the topsheet and backsheet layers are often bonded together at their peripheral edges to form a seal around the article. In use, such articles are typically positioned in the crotch portion of an undergarment for absorption of bodily exudates, and are held in place via adhesive strips positioned on the undersurface of the articles (facing the garment). Some of these articles also include wing-like or flap structures for wrapping about the user's undergarments to further secure them to a user's underwear. Such wing-like structures are frequently made from lateral extensions of the topsheet and backsheet layers.
For many women, it is entirely routine to periodically view their hygienic articles during use, so as to monitor the appearance and spread of a menses insult (so as to avoid leakage throughout the day). For some women, a concern or cause of emotional discomfort with conventional feminine hygiene absorbent personal care articles is the expanding appearance of a menses insult in the article, and specifically, the spread of the menses stain to the side edges of a product. While many women often do not mind seeing a targeted staining in the center of a pad, and then change the pad accordingly, some women prefer not to see an extensive stain, other than the centralized insult stain. In contrast, some women prefer to see an expanding stain, as this provides indication of their level of flow that day, as well as evidence that the pad is collecting such exudates. Therefore stains on a feminine care pad can have a profound influence on the consumer use experience of the pad product. Stain size and intensity can influence perceptions of cleanliness and dryness as well as the performance of a pad. Obviously, the leakage of fluids when using such articles, particularly from around the side edges of the articles, is universally a cause of emotional concern. Such leakage may occur in the narrower product dimension along the longitudinally directed side edges, or along the lateral wing or flap areas. Product leakage may lead not only to embarrassment for the consumer, but also to a general loss of confidence in use of the articles. A very vivid menses stain positioned close to the edges on a pad may convey an impression that the pad is about to leak, which therefore impacts the consumer's perception of the pad's ability to deliver a sense of security against leakage.
Various attempts have therefore been made to incorporate structures into feminine hygienic pads to separate staining, direct staining, target staining, mask staining or discolor menses staining; to make more efficient use of as much of an absorbent product as possible; and to reduce or prevent leakage. Such structures include embossed walls or channels, shaped target areas such as openings from a top surface to a lower absorbent layer, polymeric or other liquid impermeable barrier walls, and the like. However, such attempts have not been completely successful at eliminating or addressing the leakage problem, or reducing consumer concerns over the severity of staining, if it actually were to occur.
Numerous absorbent structures have also been developed for capturing and retaining voluminous menses exudates released by women during their monthly cycles. In this regard, the designs of such absorbent pads and pantiliners have been refined over time, so as to make their usage more comfortable (physically and emotionally) to consumers. For example, originally when first developed, catamenial pads were thick and bulky structures, typically using cellulosic wadding as their sole or primary absorbent layer, such as described in U.S. Pat. No. 3,124,135 to Olson. Such pads were often readily visible through a wearer's outergarments, were used in conjunction with separate belts or tabs, and proved uncomfortable for a user to wear. These older “tabbed” or belted pads distributed menses predominantly in the depth direction/axis (also known as Z-axis) of the pad, and predominantly leaked through the back of the pad. This fluid distribution was driven by a close to the body fit, due to the pad use with belt construction. These pads were typically over ¾ inch thick (approximately 19.05 mm), and employed no impervious layers to impede menses or air movement through the pad, and offered no specific distribution materials to drive lateral or longitudinal fluid distribution. These older pads needed constructions that prevented downward distribution of the red stain of menses. Because these older pads leaked through the backsheet layer, constructions were of interest which minimized the staining (or stain size) on the backsheet layer. In contrast, modern pads seek to minimize staining on the topsheet layer (from which leakage may occur as a result of such pads being fastened to the undergarment, with less close-to-body fit). Further, the older pads also did not contain any superabsorbent that might interfere with the distribution of menses within the pad. As a result, such older constructions would not work adequately on modern, garment-attached pad arrangements.
As absorbent technology advanced, superabsorbent polymer chemistry and substrate layering designs have been developed, enabling manufacturers to produce feminine absorbent products with progressively thinner configurations. As a result, feminine hygiene sanitary napkins, pads and liners have become significantly thinner and more absorbent, so as to impart both comfort and a certain inconspicuousness to a wearer. For the most part, such thinner products have provided the users and surrounding third parties, with the impression that the user is not wearing any form of menses protection in her undergarments. Such articles have employed garment attachment systems.
The modern garment-attached pads predominantly distribute menses laterally and longitudinally, and predominantly leak, when they leak, off the side edges (longitudinally directed sides, front, and back edges) rather than through the pad bottom. This leakage distribution is driven by not-so-close pad body fit, due to attachment to underwear or panties, and the pad construction. These pads are typically less than ¼ inch thick (approximately 6.35 mm), have an impervious backsheet layer to impede menses and air movement through the pad, and utilize specific distribution materials to drive lateral and longitudinal distribution. Modern pads also contain superabsorbent that can interfere with the distribution of menses within the pad. The use of superabsorbent materials in core layers can lead to gel blocking that interferes with maximized fluid absorption.
Even with these advancements in absorbency, consumers continue to experience some leakage, typically from fluid run-off from the topsheet surface. Attempts have been put forth which use combinations of specific chemistry and substrates to filter blood from menses on feminine care article. For example, filtering using a “depth filter” is described in U.S. Pat. No. 6,350,711 to Potts et al. Still another reference which describes the use of specific salts to remove colored substances from aqueous fluids is U.S. patent publication 2012/0215192 to Corbellini et al.
Menses run-off from the topsheet of thin products is often the result of various “structural” and “action-based” root causes, which cause soiling of user garments or bedding. For example, structural causes may include impeded absorbency pathways, or inability to handle fluid surges. Action-based causes may be for example, consumers experiencing leakage from improper placement of such products in their undergarments, a consumer's use of such products beyond the product's designed lifespan, consumers choosing to wear an absorbent article that is ill equipped to handle their current menses flow rate, or further still, consumer movements during their daily activities which cause menses exudates to leak off of the absorbent article. Therefore, despite the development of many different absorbent technologies and structural designs, product leakage and the resulting stains caused from such leakage continue to concern potential users of such products. A need therefore exists for pad constructions that prevent lateral and longitudinal distribution of the red stain of menses. There is a further need for absorbent structures which utilize layering structures to reduce the severity/appearance of menses staining of both a user's pad, and a user's garments or bedding. There is also a need for absorbent articles which reduce a consumer's concern over any stain that might occur, as well as articles which more efficiently use absorbent systems to take up retained liquids.